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Naval Postgraduate School
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This thesis describes a CAD-compatible circuit model for an infinitesimally thin inductive strip centered in homogeneous finline for 0.1 less than or equal to w over b less than or equal to 1.0. The model is shown to predict scattering data which agrees with data computed using the spectral domain method. Results were generated for strips of length T greater than or equal to 10 mils in X-band. By applying the scaling principle, the model is valid for any waveguide band over the normal frequency...
Topics: Electrical engineering., Finline, Discontinuity, Inductive, Strip
This thesis describes a CAD compatible circuit model for an inductive strip with finite metal thickness centered in finline with wb=1. Scattering coefficients predicted by the circuit model are in good agreement with those predicted by an electromagnetic model based on Maxwell's equations. Filter simulations using the circuit model predict responses which are in good agreement with laboratory measurements.
Topics: Electrical engineering, Electronics, Computer-aided design.
Electromagnetic scattering from rough surfaces is of prime importance in the engineering field since it affects communications, radar, remote sensing, acoustics, etc. The actual problem of scattering from rough surfaces is complicated and involves three dimensional scattering from either lossy or dielectric, electrically large surface. Integral equations are widely utilized to solve this kind of problem but this solution to the problem is generally computationally intensive. In the On-Surface...
Topics: Electrical engineering, Radiation, Linear systems, Optics., Electromagnetic scattering, Period...
This research considers communication amongst a community of earth terminals through a collection of low altitude earth oriented satellites (LASAT) . In one proposed LASAT system, all satellites are identical and simultaneous transmission of near identical signals from several satellites creates interference at the earth receivers. Frequency hop sequence (FHS) is a new form of frequency hopping (FH) and is the proposed spread spectrum LASAT communications technique considered in this research....
Topics: Telecommunication systems, Noise, Electrical engineering., Frequency hopping, satellite...
Naval Postgraduate School
by Zagourakis, Emmanouil N.
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The purpose of this study is to determine whether or not a program could be developed to examine isomorphism between parts of a VLSI layout. Many simulation files, obtained through Magic's hierarchical extractor, were analyzed in order to develop a C program to accomplish recognition in several types of gates. This recognition gives signatures in order to check for isomorphism. The development and design of the algorithms used in different parts of the program are described. Results demonstrate...
Topics: Algorithms, Electrical engineering., VLSI circuit verification, gate recognition, isomorphism...
Naval Postgraduate School
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Numerous methods exist to calculate near-fields from two-dimensional objects, however, relatively long computation times are generally required for reasonable accuracy. Computation is slowed primarily due to the calculation of near-fields using a singular kernel. The proposed work will develop an alternate, more efficient algorithm for calculating the near-fields from surface distributions. The Singularity Extraction Technique (SET) analytically extracts the contribution due to the...
Topics: Electrical engineering, Near-fields., Electromagnetic scattering, near-fields
Prediction of ionospheric propagation in polar regions tends to be difficult because of an increased number and variety of local ionospheric disturbances. Various programs have been developed to model ionospheric propagation, and one such program, IONCAP-PC 2.5, is tested for accuracy over a transpolar communications link, using noncentric measured reference data obtained from the Univercity of Leicester. The field strength values predicted by IONCAP-PC 2.5 are extended to take into...
Topics: Electrical engineering, Ionosphere., High Frequency (HF), Ionospheric Propagation
Naval Postgraduate School
by Noble, Michael Lynn
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This thesis presents a preliminary design of the electrical power system (EPS) for the Naval Postgraduate School's Petite Amateur Navy Satellite (PANSAT). The EPS is a photovoltaic silicon cell system consisting of solar array, batteries, battery charge regulator (BCR), and dc-dc convertors. The EPS provides power for up to two years of low earth orbit (480 km) operations. The solar array consists of 17 panels with thirty-two 2x4 cm solar cells in series on each panel. The cells have an...
Topics: Electrical engineering, System design., PANSAT satellite, electrical power system, battery charge...
This thesis represents an initial attempt to demonstrate aspect independent target identification of complex radar targets using annihilation filters based on the natural resonances of the targets. The Cadzow-Solomon signal processing algorithm is tested to determine its suitability for the task of extracting the poles from complex targets to a degree of accuracy required for successful implementation of an annihilation filtering target identification system. This testing was conducted through...
Topics: Electrical engineering, Radar, Signal processing., Pole Extraction, Cadzow-Solomon, Annihilation...
Naval Postgraduate School
by Ives, Robert W.
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Multi-frequency modulation (MFM) has been developed at NPS using both quadrature-phase-shift-keyed (QPSK) and quadrature-amplitude-modulated (QAM) signals with good bit error performance at reasonable signal-to-noise ratios. Improved performance can be achieved by the introduction of error control coding. This report documents a Fortran simulation of the implementation of error control coding into an MFM communication link with additive white Gaussian noise. Four Reed-Solomon codes were...
Topics: Electrical engineering, Cybernetics, Telecommunication systems., Multifrequency Modulation,...
Naval Postgraduate School
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The Kalman filter is used to provide estimates of the position and velocity of a storm based upon observation of the storm's longitude and latitude. Nonstationary noise is shown to degrade the performance of the filter and cause tracking divergence. Time varying values for the noise covariance matricies R and Q, and the addition of an external forcing function to the filter, effectively compensated for this tracking error. Results for the simulations show significant performance advantages of...
Topics: Electrical engineering, Cyclones, Latitude, Longitude, Storms, Weather forecasting, Tropics.,...
Several heuristics and algorithms have been developed to find minimal sum-of-products expressions in binary logic. Most of them use prime implicants during minimization process. An efficient search strategy has been developed for finding minimal sum-of-products expressions for multiple-valued logic (MVL) functions by using the constrained implicants set concept. The search space can be considerably reduced over the only other known exact minimization technique and exhaustive search. The primary...
Topics: Electrical engineering, Computer engineering, Computer input-output equipment, Constrained...
Naval Postgraduate School
by Wilhelm, Joseph Arthur, Jr.
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The Naval Post Graduate School has obtained software which can be used for the thermal analysis of an electronic component. This software includes two versions, one for steady state analysis and the other for transient analysis. Each version consists of two programs, a model builder and a thermal analyzer. This thesis describes a user friendly, menu driven specific model builder which may be used to rapidly generate a thermal model, containing up to 750 nodes, for a microcircuit die. This model...
Topics: Electrical engineering, Thermal analysis, Computer programs, Thermal Analysis, Computer Aided,...
Naval Postgraduate School
by Vourazelis, Dimitrios G.
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This thesis is a design of an alternative system which may provide heating to the Naval Postgraduate School swimming pool. Particularly, it is a solar heating/photovoltaic system designed for a better efficiency and less cost of installation and maintenance. Principles of heat transfer, control and fluid dynamics theory are used for the determination of this heating system elements. The feasibility of its installation and use is analyzed.
Topics: Photovoltaic power generation, Solar energy, Electrical engineering., Optimization, Solar Heating,...
Progress in computers during the past two decades has sparked the development of many useful high frequency (HF) ionospheric propagation prediction codes. The high-latitude (polar) ionosphere still remains as the most difficult propagation region to predict. A 'Non centric database of collected high-latitude signal and noise measurements was obtained during 1988 and 1989 by the University of Leicester, UK The Advanced Prophet 4.0 HF Ionospheric Propagation Prediction Code was exercised and...
Topics: Electrical engineering, Computer programming, Radio frequency, Communication., High Frequency (HF),...
Naval Postgraduate School
by Thornlow, Robert Timothy
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Several techniques for estimation of the power spectral density (PSD) , or simply the spectrum, of discretely sampled short data sequences are investigated in this thesis. These techniques are directly based on the fast Fourier transform (FFT) of the data sequence. However, an extrapolated version of the original data sequence will be used instead of the original. The aim is to enhance the resolution of the true spectral components of the signal without adding any false frequency components....
Topics: Electrical engineering, Electronic data processing., Data Extrapolation, Periodogram, AR spectral...
Electronic support measures (ESM) systems play an increasingly important role in modern warfare and can influence the outcome of a military engagement. The application of ESM can be extended to anti-guerrilla and anti-drug operations where law enforcement agencies can exploit the fact that their presence is inducing the outlaw to depend more on radio communications to coordinate their activities. When a propagation path of no more than one reflection at the ionosphere (1-hop) can be assumed,...
Topics: Electrical engineering, Electronics in military engineering, Modeling., Single-Sight-Location,...
Naval Postgraduate School
by Sudjiwo
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The open-end resonator in suspended substrate transmission line was analyzed in terms of two open-end discontinuities on a line segment. A procedure for computing the resonant frequency and constant of propagation was demonstrated using a full wave analysis. The fringing capacitance was computed using an equivalent length extension model and a transmission line circuit model. The characteristic equation was derived using Galerkin's method applied in the Fourier transform domain. The calculation...
Topics: Systems engineering, Electrical engineering., Spectral Domain Approach, Suspended Substrate Line,...
Naval Postgraduate School
by Kaoutskis, Michael T.
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Several data compression schemes have been investigated for reducing storage space and transfer time via a computer network. The primary goal of this thesis is to develop a new scheme for data compression ratio better than the already existing schemes. The main approach adopted by this research is a combination of dictionary look up and entropy source coding.
Topics: Electrical engineering, Algorithms, Encyclopedias and dictionaries, Computer networks., Entropy...
Naval Postgraduate School
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The capability of an electromagnetic radiating system depends on its ability to operate effectively in a complex environment, where its pattern performance can be limited by pattern distortion effects. On a modern military ship, this task is complicated by the large number of systems that are competing for prime locations. It is recommended, therefore, that a given situation be studied systematically, looking at individual pieces of the problem separately and developing intermediate...
Topics: Electrical engineering, Modeling, Radio frequency, Radio wave propagation., Inverted Cone Antenna,...
Testability issues concerning the need for including Design for Testability (DFT) techniques in VLSI (Very Large Scale Integration) designs are discussed. Types of fault models, the use of fault simulation and the DFT techniques of Scan Path and Built in Test are described. An engineering methodology that uses the Genesil Silicon Compiler to produce a VLSI design, DFT-CHIP, which utilizes the DFT Scan Path technique is presented. Included are the procedures for using Genesil's simulation,...
Topics: Electrical engineering, Computer-aided design., Design for testability, VLSI, Genesil Silicon...